Cellular service is encountering a problem already as they realize their model of selling voice and SMS plans are beginning to be replaced by data plans. ISPs like Verizon and Comcast are also in the same boat as people begin to figure out that instead of paying for cable and telephone service they can use legal alternatives such as Hulu, iTunes, Amazon, and illegal alternatives for media content.That's why ISPs want to enact a data cap, to prevent people from switching their services over and relying solely on the internet for everything (not to mention that they built their network in a way where when you pay for a line your not truly being given access to what you pay for).

As to how that affects us. Well, I believe Google's strategy is not for everyone to use their Android or Chrome OS. Sure they would like us to (since it makes their job easier to collect data on us) but their overall profit is from selling advertisements and information regardless of what platform the users are on. I don't think they would stop offering their services to other platforms (not unless they had say like 99% of the marketshare). Even if they had majority, the uncaptured % is still more money they could make.

Would an official Google phone designed by Google themselves be more competition? Yup. But that just means Nokia and Maemo have to step up the challenge and provider an alternative for those people who don't want to jump into Google's reach completly.

Edit: As to how cellullar companies would take it.. well right now their solution is to enact a cap or to charge you more. For those with relatively well priced "unlimited" data plans I would hold on to those.

I can't imagine Google would enter the telecommunication business themselves. To many government regulations and hoops to jump through right now. And most of their actions that have seem ISP related were for their own internal networks or to increase Google's capacity at datacenters.